Corals and Bryozoans of the Lower Heldkrberg. 159 



eating series ; lower surface covered by an epitheca which is strongly wrinkled 

 concentrically, and having fine, radiating lines formed by the recumbent portion 

 of the cell-tubes. 



This species differs" from C. maculuta, plate xvi, figs. 5-11, in being incrust- 

 ing, the frond much thinner, the cells smaller, more oblique and not radiating 

 from a centre. 



Formation awl locality. Lower Helderberg group, near Clarksville, N. Y. 



Ceramopora maculate. 



(PLATE XVI, FiGS. 5-11.) 



Ceramopora macnlata, Hall. Twenty-sixth Rep. N. Y. State Mas. Nat. Hist., 



p. 108. 1874. 



Bryozoum discoidal, flattened or concave on the lower side, covered by an 

 epitheca having strong concentric wrinkles. Cells polygonal, radiating from the 

 centre ; diameter at aperture one-half of one millimetre ; there are frequent maculae 

 where the cells are larger — about once and one-half as large as those on other 

 portions; cell-walls sometimes slightly elevated at the angles, forming low spine- 

 like projections at the centre of the disc ; the cell-tubes in the central portions 

 are at right angles to the surface, becoming more oblique as they approach 

 the margin, where they are nearly rectangular to the central ones; the diame- 

 ters of the discs vary from six to forty mm. ; thickness of the larger specimens 

 .from two to three mm. 



This species resembles C. imbricata of the Niagara limestone, but differs in 

 the less distinctly hooded apertures ; the maculae are more obscure and less 

 strongly divided and radiate, and it also grows to a much larger size. 



Formation and localities. Lower Helderberg group, Clarksville and Scho- 

 harie, N. Y. 



Ceramopora (Berenicea) maxima. 



(PLATE XVI, FIG. 12.) 



Ceraiwvpora (Berenicea) maxima, Hall. Twenty-sixth Rep. N. Y. State Mus. Nat. 



Hist., p. 109. 1874. 



Bryozoum of a depressed-convex form, composed of cells which radiate from 

 the centre of the disc, and open laterally, being nearly at right angles to the 

 plane of the disc at the centre, and becoming more prone as they approach the 

 margin ; apertures irregularly hexagonal, somewhat elongated from the projec- 

 tion of the lower margin ; diameter of aperture about one mm. ; cell- walls thick, 

 obscurely striate inside ; their margins, at the angles of the cells, prolonged in 

 a spine-like process ; lower surface unknown. 



The single specimen found measures eighteen mm. in diameter; it has 

 the general features of those Palaeozoic species usually referred to Berenicea, 

 but is much larger than their usual size. It resembles a Michelina with very 



